The Tibetan Sedimentary Sequence is the uppermost tectonic unit of the Himalayan belt and it is a typical passive margin sequence deposited on the Indian plate. It has been affected by several tectonic phases (GODIN 2003; RATCHBACHER et alii, 2004; ANTOLIN et alii, 2011) linked to both continental collision and later exhumation. During continental collision the tectonic unit experienced low-grade metamorphism (CROUZET et alii, 2007; DUNKL et alii, 2011), and SW verging folds and related axial plane foliation developed. The bottom of this low-grade metamorphic unit constitutes nowadays the hanging-wall rocks of a large scale detachment fault (the South Tibetan Detachment System: STDS) that divides it from the lower high to medium-grade metamorphic rock of the Higher Himalayan Crystallines (HHC). The role of large scale detachment fault systems is of crucial importance in the understanding the evolution of orogenic systems. In particolar the activity of the South Tibetan Detachment System (BURCHFIELD et alii, 1992) joined with the partly coeval lower Main Central Thrust (GODIN et alii, 2006), played a crucial role in the exhumation and extrusion of the high grade metamorphic rocks. The knowledge of the thermal and structural activity of the STDS can give a fundamental contribution to discriminate among the different proposed tectonic models. Anyway most of the structural and thermal studies focused on the kinematic and thermal profiles of the footwall rocks (JESSUP et alii, 2008; COTTLE et alii, 2011) of the STDS and only few studies have been concentrated on the hanging-wall rocks (COTTLE et alii, 2007; MONTOMOLI et alii, 2010; KELLETet alii, 2012).
Decoupling of Tibetan sedimentary sequence and Higher Himalayan Crystallines: Strain and paleotemperature constrains for the South Tibetan detachment system
MONTOMOLI, CHIARA;
2012-01-01
Abstract
The Tibetan Sedimentary Sequence is the uppermost tectonic unit of the Himalayan belt and it is a typical passive margin sequence deposited on the Indian plate. It has been affected by several tectonic phases (GODIN 2003; RATCHBACHER et alii, 2004; ANTOLIN et alii, 2011) linked to both continental collision and later exhumation. During continental collision the tectonic unit experienced low-grade metamorphism (CROUZET et alii, 2007; DUNKL et alii, 2011), and SW verging folds and related axial plane foliation developed. The bottom of this low-grade metamorphic unit constitutes nowadays the hanging-wall rocks of a large scale detachment fault (the South Tibetan Detachment System: STDS) that divides it from the lower high to medium-grade metamorphic rock of the Higher Himalayan Crystallines (HHC). The role of large scale detachment fault systems is of crucial importance in the understanding the evolution of orogenic systems. In particolar the activity of the South Tibetan Detachment System (BURCHFIELD et alii, 1992) joined with the partly coeval lower Main Central Thrust (GODIN et alii, 2006), played a crucial role in the exhumation and extrusion of the high grade metamorphic rocks. The knowledge of the thermal and structural activity of the STDS can give a fundamental contribution to discriminate among the different proposed tectonic models. Anyway most of the structural and thermal studies focused on the kinematic and thermal profiles of the footwall rocks (JESSUP et alii, 2008; COTTLE et alii, 2011) of the STDS and only few studies have been concentrated on the hanging-wall rocks (COTTLE et alii, 2007; MONTOMOLI et alii, 2010; KELLETet alii, 2012).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
